Abstract Alcohol and illicit drug use remain highly prevalent in the US, and epidemiological surveillance surveys estimate that over 20.6 million individuals (~ 8% of the US population) meet standard diagnostic thresholds for substance use disorders (SAMHSA, 2011). Outpatient substance abuse treatment is the predominate method of treatment in the US for SUDs, typically involving intermittent contact between clinician and client through weekly individual and/or group therapy sessions (SAMHSA, 2012). Unfortunately, relapse and premature treatment discontinuation are quite common in outpatient treatment (Scott et al., 2005; White, 2008). However, a strong emotional bond between clinician and client (i.e., therapeutic alliance) early in treatment has been found to enhance treatment retention and effectiveness (Barber et al., 2001; Meier et al., 2005; Miller et al., 2006; Thompson et al., 2007). Establishing and maintaining a strong therapeutic alliance in outpatient treatment is challenging due to the intermittent nature of weekly contact, leaving clinicians with a deficit of information regarding client recovery. Regular client monitoring between weekly sessions could correct such deficits and reduce the likelihood of client relapse by giving clinicians timely and accurate data to inform client- centered treatment. The proposed client check-in monitoring system (CIMS) will use phone-based interactive voice response (IVR) technology to obtain client data between weekly treatment sessions regarding motivations, cravings, risk/protective factors, and substance use behaviors. The system will generate automated brief summary reports to assist clinicians in assessing treatment needs and tailoring services. The proposed technology could ultimately be deployed throughout the national network of outpatient substance abuse treatment providers to facilitate the delivery of client-centered care, strengthen therapeutic alliance, enhance client engagement, and improve treatment retention and outcomes. Thus, the proposed technology could have high public health impact.